Workaround:
* Duplicate smart object layer
* Rasterize the duplicate
* Select-all, copy to new document, select-all in new document, copy back to first document (Previous rasterizing step leaves off-the-canvas pixels)
* Re-smart-object the duplicate (If you want to still use as smart object)
* Keep original hidden, if you want to keep it around (Massive resizing means much larger filesize though)
* Any time you update the contents of the original smart object, go through workaround steps again

Instead of canvas sizing to 8x8px, using the cropping tool with "Delete Cropped Pixels" checked. Even though the smart object's pixels aren't truly going to be deleted, shouldn't it honor treating those pixels as deleted, and not use them in any type of calculations?

(I just tried this alternate method, and the behavior doesn't change.)

It was really nice to think I could open an original photograph to scan, immediately convert it to a smart object, crop, and resize. This would leave the original "tucked away", unmodified.

Then, if I needed to resize again later, I didn't have to worry about re-cropping because the resampling went different and changed where the crop needed to happen.

If you delete the cropped pixels, then the cropped pixels are not used for resampling, because they're gone.

What you describe is exactly how smart objects work - the original is there, unmodified. You can crop and resize it all you like, and the original is still available to tweak, and any further resizing is done from the original.

not really, since the smart object always retains it's original pixels and resamples from them. The crop tool only affects the plain pixel layers, it can't affect the original data for your smart object.